textproduct: Quad Cities

KEY MESSAGES

- Accumulating snow to develop this evening north of I-80 before ending prior to daybreak Wednesday, with highest amounts (2-4"+) possible near the Highway 20 corridor. The cold temperatures will lead to slippery road conditions.

- An Arctic front may bring a period of strong gusty snow showers Wednesday mid afternoon into evening. Periods of low visibility in falling snow and blowing snow, and a refreeze of any moisture on roadways could lead to travel impacts.

- Even colder temperatures, including some highs only around zero, becoming probable Friday and Saturday behind a reinforcing cold front on Thursday night. Teens below zero are possible!

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 347 AM CST Tue Jan 20 2026

Well advertised pair of clipper systems still progged to impact the region over the next couple of days. The first system is currently diving southeastward across Alberta early this morning. As this approaches, an initial slug of warm, moist advection will aid in lowering ceilings and increasing snow chances this evening north of I-80. However, by late evening and overnight the right entrance region of a strengthening upper jet (115+ kt H3) coupled with a baroclinic zone will foster ramping wind convergence and tightening of the thermal gradient (Fgen) resulting in increased lift particularly near the top of the H8-H7 layer. This should focus a more narrow Fgen band of snow, potentially moderate in intensity at times. There still remains some disagreement on the exact placement of the band, although a majority of the 00z CAMs and NAM/GFS deterministic guidance has trended 30-70 miles further south and a bit wetter while the ECMWF and lower resolution ensemble guidance is predominantly a bit further north and drier. Latest PWAT analysis lends support to much of the short term guidance depicting a marked increase of moisture throughout the column to near 0.3 inches or close to the 75th percentile for the date per SPC sounding climatology for DVN raobs. An inspection of soundings and model cross-sections support much of the saturated lift residing near the top of the DGZ, especially near the Highway 20 corridor in NE Iowa and far N Illinois. This would support a fluffy dendritic snow able to accumulate efficiently given the cold temperatures and absence of wind to fracture the crystals. Past few SPC SREF runs indicate high probabilities of the DGZ being greater than 100 mb further supporting higher snow to liquid ratios potentially 20-25:1 or higher within the main fgen snow band. Again there remains still some disagreement on the location, but a preponderance of the hi-res guidance and juxtaposition of strong frontal forcing and best thermal profile favor roughly near the Highway 20 corridor through the IL/WI border. Snowfall rates are likely to be 0.5 to 1" per hour at times, with the 00z HREF even showing 30-40% probabilities for a few hour window centered either side of midnight for >1" per hour rates in this same corridor. This forcing rapidly wanes by 09z-12z Wednesday. Taking into account PWATs, strength of forcing and duration along with rates lends to confidence in 2-4" snowfall amounts for the Highway 20 corridor where we have coordinated a Winter Weather Advisory. If the forcing increases or any further cooling occur in the low/mid levels then there would be the potential to see higher amounts possibly up to locally 6". As with these stronger Fgen events there should be a rather sharp gradient either side of the band going from a few inches to a dusting/trace, and this right now looks to be near Highway 30 or possibly near I-80 if the system maintains it's more southerly jog from the 00z guidance. We should get a short break in the snow for much of Wednesday morning. However, attention will then turn to our next clipper system which is slated to pass to our north Wednesday PM/night, but swing a cold front through the region. This has the potential to produce higher impacts due to strong winds of 30-40+ mph and blowing of the fresh 2"+ of snow near Highway 20 with periods of greatly reduced visibility by late afternoon through evening. Ahead of this front temperatures on Wednesday are likely to reach or exceed the freezing mark, but mainly south of Highway 30. However, should it warm more than expected near Highway 20 it could take the edge off some of the blowing snow potential. Nonetheless, the blowing snow potential and impacts to travel will need to be monitored closely over the next 24+ hours. In addition, by late in the day and evening with strong cold advection settling in helping to foster deeper mixing and some low level instability tapping into the DGZ all look to allow for vigorous snow shower and localized snow squall potential with periods of greatly reduced visibility in snowfall and blowing snow with also potential for a rapid freeze in those areas that manage to get above freezing during the day. Will definitely need to keep tabs on the forecast and be prepared to make changes to travel plans if the blowing snow and vigorous snow showers come to fruition by later in the afternoon through evening potentially impacting the commute. Snow amounts look to be under an inch.

LONG TERM /THURSDAY THROUGH MONDAY/

Issued at 347 AM CST Tue Jan 20 2026

The long wave upper trough currently extends almost the width of the continent and as far equatorward as the Mid South, which will be difficult to budge in the next two weeks, if not longer, thus the region is susceptible to colder air shots. The active zone of substantial precipitation-making systems of note will tend to be south of the area, however lower amplitude light snow makers, enough to cause problems with cold and winds, will traverse the Midwest. Timing of these and specific tracks are low confidence three plus days out.

As mentioned the background pattern supports cold reinforcement and that is exactly what is forecast. A pronounced 500 mb low is forecast to carve into the trough with heights forecast 3-4 sigma below normal over central Canada into the northern Great Lakes (impressive for the coldest time of year). That will result in an arctic front Thursday night it appears. Tough to tell if it would come with as much wind fanfare, but right now it looks like it would not due to less baroclinicity. However, the cold air behind it will be more pronounced and an arctic high pressure of a stout 1050+ mb settles in nearby early in the weekend. With H85 temperatures forecast to be -25C to -30C (bottom few percentile for January), it is becoming more likely based on NBM probability trends that nighttime lows Friday and Saturday nights will be in the negative double digits for some, and highs both days likely to struggle to get much above if even above zero, especially north where some snow cover should exist. On the snow cover note, some model membership in the NBM can struggle with that, and some modification of the arctic air is probable. But even if temperatures do not end up as cold as deterministically forecast now, the high confidence in well below normal temperatures at the coldest time of the year is a key message.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1125 AM CST Tue Jan 20 2026

VFR conditions to start the forecast period with high clouds rolling in from the west. A weak clipper is set to move across northern IA this evening bringing light snow. Most of this snow will stay along northern IA with KDBQ seeing the lion's share of the snow. High res guidance suggests possible snowfall rates of half an inch per hour between 04Z and 07Z. Farther south for KCID lighter snowfall rates will be possible and KMLI may only see a dusting. With the passage of this clipper look for CIGS to drop to MVFR/IFR before improving back to VFR tomorrow morning. Lastly, there will be a window for some low level wind shear at BRL tonight as strong southwesterlies feed into the passing clipper.

HYDROLOGY

Issued at 145 PM CST Mon Jan 19 2026

On the Rock River just downstream of Joslin, or more proper, near the railroad bridge immediately downstream of the I-80 bridge, continues to have a ice formation related ice jam being reported. This jam has brought elevated stages at Joslin, and a report of just out of bank flooding near Cleveland IL. At this time, we're considering a Flood Watch for this area of the Rock River.

The signal has strengthened for the forecast area to remain mostly below freezing the next ten days, including a couple substantial cold bouts of subzero air -- the current one and late this week into the weekend. Ice has rapidly developed on some area rivers in the last 48 hours, including the Lower Rock River. More ice development and at an even quicker rate will be favored during the coldest stretches, and could support some freeze up jams especially in favored locations such as the Lower Rock. Streamflows are currently near the 50th percentile for January (i.e. near the long term normal). If they were higher, that would really raise concerns right now. Will keep an eye out for more honed in messaging and Flood Warnings if we receive specific reports of developing impactful ice jams.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Winter Weather Advisory from 6 PM this evening to 6 AM CST Wednesday for IAZ040>042. IL...Winter Weather Advisory from 6 PM this evening to 6 AM CST Wednesday for ILZ001-002. MO...None.